For the sixth time, the German special interest group on Distributed Arti?cial Intelligence in cooperation with the Steering Committee of MATES organized the German Conference on Multiagent System Technologies - MATES 2008. This conference, which took place during September 23-26, 2008 in Kaisersla- ern, followed a series of successful predecessor conferences in Erfurt (2003, 2004, and 2006), Koblenz (2005), and Leipzig (2007). MATES 2008 was co-located with the 31st German Conference on Arti?cial Intelligence (KI 2008) and was hosted by the University of Kaiserslautern and the German Research Center for Arti?cial Intelligence (DFKI). As in recent years, MATES 2008 provided a distinguished, lively, and - terdisciplinary forum for researchers, users, and developers of agent technology to present and discuss the latest advances of research and development in the area of autonomous agents and multiagent systems. Accordingly, the topics of MATES 2008 covered the whole range: from the theory to applications of agent and multiagent technology. In all, 35 papers were submitted from authors from 11 countries. The accepted 16 full papers included in this proceedings volume and presented as talks at the conference were chosen based on a thorough and highly selective review process. Each paper was reviewed and discussed by at least three Program Committee members and revised according to their c- ments. We believe that the papers of this volume are a representative snapshot of current research and contribute to both theoretical and applied aspects of autonomous agents and multiagent systems.